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Las estructuras cristalinas de los complejos EF-G-ribosoma atrapados en estados intermedios de translocación
Jie Zhou1, Laura Lancaster, John Paul Donohue
1Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA.
Science (New York, N.Y.)
|July 2, 2013
Resumen
El ribosoma es el ribosoma.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología Estructural Biología Estructural
- La bioquímica es la bioquímica.
Sus antecedentes:
- La síntesis de proteínas se basa en el ARN mensajero (ARNm) y la translocación del ARN de transferencia (ARNt) a través del ribosoma.
- El mecanismo preciso de este paso crucial de la translocación ribosómica sigue siendo incompletamente entendido.
Objetivo del estudio:
- Para dilucidar los mecanismos moleculares subyacentes a la translocación ribosómica.
- Para capturar y analizar los estados intermedios del complejo ribosoma-ARNm-ARNt-EF-G durante la translocación.
Principales métodos:
- Se empleó cristalografía de rayos X para determinar las estructuras de los complejos de ribosomas de Thermus.
- Los complejos fueron atrapados usando GDPNP o ácido fusídico para visualizar estados intermedios de translocación.
Principales resultados:
- Se observaron cambios conformacionales a gran escala, incluida la rotación de la cabeza y el cuerpo de la subunidad 30S.
- Los extremos del receptor de ARNt identificado en el sitio 50S E y los bucles del tallo anticodón en posiciones P-E intermedias.
- Se han descubierto bases de ARNr 16S conservadas que actúan potencialmente como un mecanismo de trinquete translocacional.
Conclusiones:
- El estudio revela cambios conformacionales clave y estados intermedios en la translocación ribosómica.
- Identificaron potenciales "palas" moleculares dentro del ribosoma que regulan el movimiento del ARNm.
- Proporciona nuevos conocimientos sobre el intrincado mecanismo de la síntesis de proteínas.
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